Zambia is negotiating a critical minerals deal with the US government after "decoupling" it from a separate health funding agreement it signed on Thursday, its foreign minister said.

"There was this (Memorandum of Understanding) on health and another on critical minerals, and we were saying that these need to be decoupled, and this has been done," Mulambo Haimbe said at a signing ceremony for the health pact, which will see the US provide $1.5 billion in funding.

Asked for more details about the minerals deal, the minister said it was "still being negotiated" but declined to elaborate.

Zambia had resisted an agreement with the United States that would directly link funding for its health sector with allowing greater US access to minerals.

The minister did not specify which minerals Zambia is considering granting the US access to.

The Southern African country is the second-largest copper producer in Sub-Saharan Africa after the Democratic Republic of Congo.